Electro-optical image composite display

ABSTRACT

Electro-optical display system for providing a composite display of an optical image wherein a first image provided by means of a cathode ray display device is superpositioned onto a second image derived from hard copy information such as slides, maps or other character information. The system is comprised of a cathode ray tube with suitable means for directing a first light image generated by the cathode ray tube onto the photocathode of an image intensifier. The second image which may be projected by means of a slide projector is also focused onto the photocathode of the image intensifier. These two images directed onto the photocathode generate an electron image corresponding to the composite image of the first and second image. This electron image is then accelerated and amplified through the image intensifier to provide a visible light display by means of a suitable phosphor positioned at the opposite end of the image intensifier with respect to the photocathode. This output visible image is a composite image of the first two images.

U5-"O8 -73 XR 39732-9428 I United States Patent 1 [111 3,732,428

Spangler 1 May 8, 1973 [54] ELECTRO-OPTICAL IMAGE Primary Examiner-David Schonberg COMPOSITE DISPLAY Assistant Examiner-John W. Leonard [75] Inventor: Murry J. Spangler, Ellicott City, y- Henson and RenZ [57] ABSTRACT ,[73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Electro-optical display system for providing a composite display of an optical image wherein a first [22] Flle J 1971 image provided by means of a cathode ray display [21] Appl. No: 106 329 device is superpositioned onto a second image derived' from hard copy information such as slides, maps or other character information. The system is comprised /8 of a cathode ray tube with suitable means for directing 350/17 a first light image generated by the cathode ray tube [51] Int. Cl ..H0lj 31/50, G02b 27/14 onto the photocathode of an image intensifier. The [58] Field of Search ..350/174, 171; second image which may be projected by means of a 250/213 VT, 83.3 HP; 178/6.8 slide projector is also focused onto the photocathode of the image intensifier. These two images directed 56 R f r Cit d onto the photocathode generate an electron image corresponding to the composite image of the first and UNITED STATES PATENT second image. This electron image is then accelerated 3,443,105 5/1969 Scidmore et al. ..250/2l3 VT 'i f the image intenlfier Provide 3 297 822 1/1967 Braid "350/174 UX a vislble light display by means of a suitable phosphor 3 440 428 4/1969 Kazan ....250 213 VT Positionfid at the Opposite end of the image intensifier with respect to the photocathode. This output visible image is a composite image of the first two images.

2 Claims, 1 Drawing Figure 22 i2 3 42 E p. I= i: a; t. e O l k ELECTRO-OPTICAL IMAGE COMPOSITE DISPLAY BACKGROUND OF THE INVENTION This invention relates to a method and apparatus for mixing auxiliary hard copy data such as maps, vectors, format, characters, etc. from an optical slide projector with an electrically generated dynamic display data for generated dynamic display data may be in the form of a conventional cathode ray tube display screen. There are many applications wherein it is desirable to have an effective means of projecting hard copy slide information directly onto the phosphor of a cathode ray tube simultaneously with electrically generated dynamic information. Examples of where such techniques may be found useful are air traffic control centers, satellite control centers, inventory control centers, area surveillance and weather tracking systems where area maps, information bearing alphanumerics, lines, vectors or other nonmoving data can be usefully displayed along with the dynamic electrical data available from devices such as radar or a computer. One present system now utilized in the industry is to project the hard copy data onto a cathode ray tube phosphor screen through one or more optical ports at the rear of the cathode ray tube. This method requires a relatively high power projection lamp or lamps and produces a background brightness resulting in reduced contrast and overall effectiveness of the electrically generated display. The cathode ray tube also must have a relatively thin phosphor which may cause poor quality in the projected data since the image has to penetrate the cathode ray tube phosphor.

SUMMARY OF THE INVENTION This invention is directed to an optical system which utilizes a cathode ray tube of conventional design for providing a first image representative of the dynamic information. A second image provided by. means of hard copy data is projected by means of a slide projector and both the first and second-images generated by these two devices are imaged via a beam splitter onto the photocathode of an image converter tube. As a result, a photoelectron image is generated from the photocathode of the image converter tube which is a composite image of the two optical images projected onto the photocathode. The photoelectron image is accelerated and focused onto a phosphor display screen which thereby provides a composite of the hard copy data from the slide projector and the dynamic information from the cathode ray tube in a visible display.

BRIEF DESCRIPTION OF THE DRAWING For a better understanding of the invention, reference may be had to the preferred embodiment, exemplary of the invention illustrating a schematic diagram embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring in detail to the drawing, a cathode ray tube is illustrated which may be of any suitable type which includes an envelope 12, and a faceplate portion 14. The faceplate portion 14 may be of a fiber optic presentation on a display screen. The electrical 1O type structure and a phosphor screen 16 is provided on the inner surface of the faceplate 14. An electron gun 18 is provided at the opposite end of the envelope 12 and generates an electron beam which is scanned by any suitable electrostatic or electromatic deflection means such as the coil 20 for deflecting the electron beam in a suitable scanning pattern over the phosphor screen 16 to provide a dynamic image representative of information applied to the electron gun 18. This electrical information applied to the electron gun 18 may be in the form of radar or computer information which is of a dynamic nature in information. The light image generated by the phosphor layer 16 is directed through a half silvered mirror 22 and focused by means ofa lens 24 onto the photocathode 26 of an image converter tube 30.

The hard copy information which may be in the form of a map, for example, is projected by means of a slide or film projector 40 onto the half silvered layer 22. The light image from the slide projector 40 will be reflected by the mirror 22 through the focusing lens 24 onto the photocathode 26 of the image converter 30.

The result is that the two light images generated by the cathode ray tube 10 and the slide projector 40 are projected onto the photocathode 26 and generate an electron image corresponding to the composite images. The image converter or amplifier 30 may also be of any suitable design and consists of an envelope 32 having an input window 34 and an output window 36. The image converter tube 30 may be of any suitable type and may be of an electrostatic focus or electromagnetic focus and in the specific embodiment shown a focus coil 38 is illustrated for focusing the electron image from the photocathode 26 onto a phosphor output screen 42. A suitable accelerating voltage is provided between the photocathode 26 and the output screen 42 by means of any suitable potential source such as the battery 44. In this manner, the photoelectron image emitted by the photocathode 26 in response to the pro jection of the two images from the cathode ray tube 10 and the projector 40 are imaged on the output I phosphor 42 to provide a visible image corresponding to the information within the photoelectron image.

By this combination one is able to maintain control of the brightnesses of the two sources 10 and 40 so as to obtain a desired contrast on the output image provided on the phosphor screen 42. In addition, the image converter provides means of amplification of the image directed onto the photocathode 26 to provide a high brightness output image.

I claim as my invention:

1. An electro-optical system comprising a cathode ray display means for providing a first image representative of dynamic information of a scene, a second means for providing a second image representative of stationary information of the scene and different than said first image, an image converter tube comprising a photocathode and an output phosphor display screen, a half silvered mirror positioned in the optical path between said display means, said second means and said image converter tube so as to combine said first and second images and direct the composite image display to said image converter tube, and an optical system for focusing said first and second images onto the photocathode of said image converter tube to put screen to provide a visible display representative of 5 the composite display of said first and second images.

2. A system as set forth in claim 1 wherein said first information is of a moving nature and wherein said second information is of a relatively stationary information with respect to said first information. 

1. An electro-optical system comprising a cathode ray display means for providing a first image representative of dynamic information of a scene, a second means for providing a second image representative of stationary information of the scene and different than said first image, an image converter tube comprising a photocathode and an output phosphor display screen, a half silvered mirror positioned in the optical path between said display means, said second means and said image converter tube so as to combine said first and second images and direct the composite image display to said image converter tube, and an optical system for focusing said first and second images onto the photocathode of said image converter tube to generate an electron image from said photocathode representative of the composite display of said first and second images, and means for accelerating and focusing said photoelectron image onto said phosphor output screen to provide a visible display representative of the composite display of said first and second images.
 2. A system as set forth in claim 1 wherein said first information is of a moving nature and wherein said second information is of a relatively stationary information with respect to said first information. 